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"We just don't know the motive or cause of death, but we do have four adults and two children [dead]," Memphis police Lt. Jerry Guin told the paper.

Rob Robinson told the Commercial Appeal that he was the landlord for the brick, single-family house that rented for $550 per month.

"They were very nice, very polite to me," Robinson told the paper of the residents.

"It's kind of surprising, actually. I've never had any trouble with them, no damage to the property. They paid their rent and even helped with repairs and stuff."

Neighbor Leo Baker told CNN affiliate WMC-TV he has lived nearby for 10 years but did not know the residents of the home.

"It's sad you come home to find out something like this has gone on," Baker said. "It's kind of sad, and scary, too."

Video footage showed emergency vehicles on the scene, with people embracing in rainy weather outside police tape surrounding the home.

"I've been on a scene where there were one or two or three [victims], but I don't remember anything this large," Guin told the Commercial Appeal.

The newspaper reported that the shooting appeared to be the city's deadliest mass killing since 1973, when 28-year-old David Sanders randomly shot and killed five people before being shot dead by police.

In 2000, police said firefighter Frederick Williams confessed to a shooting in Memphis in which four people were killed -- his wife, a sheriff's deputy and two fellow firefighters.E-mail to a friend